The term “actuator” as used herein designates a component or an assembly with which electrical energy is converted into mechanical energy, whereby a movement of a part of the actuator is generated which can be transferred to an element to be actuated. An actuator of this type can advantageously be used inter alia in fluid valve technology, e.g. in order to actuate a valve.
A diaphragm actuator is characterised in that it has a diaphragm layer which is used to convert the electrical energy into mechanical energy. For this purpose, the diaphragm layer can typically be formed from an electro-active polymer which e.g. expands or contracts when a voltage is applied. In this way the electrical energy applied by the application of voltage is converted into mechanical energy, which leads to a movement of an output part of the actuator.
Suitable electro-active polymers are e.g. silicone, polyurethane and acrylate.
It is known from the prior art to stack such diaphragm actuators on top of one another to form a stacked diaphragm actuator in order to increase the available force thereof. For example, a stacked diaphragm actuator of this type is known from WO 2008/083325 A, in which each diaphragm layer is clamped in between two frame parts. A plurality of these diaphragm actuators are stacked one above the other in order to form the stacked diaphragm actuator.
In stacked diaphragm actuators of this type it has proved to be disadvantageous that they require a lot of space since the individual diaphragm actuators each lie on top of one another via their frame parts. However, the frames are of greater height than the active regions of the diaphragm layers which generate the movement, i.e. the regions of the diaphragm layers which are disposed between electrode layers. Much space thereby is wasted.
It is the object of the invention to form a diaphragm actuator which can exert a high level of force but nevertheless requires little installation space.